Plug-in connectors comprise a plug-in connector and a mounted receptacle, or two mating plug-in connectors are used for connecting and disconnecting multiple-wire cables.
A variety of arrangements and devices are known for holding a pair of connectors together securely, in their plugged-in condition. The friction of the plugged-in contacts may provide sufficient retention. Resilient detents are used widely, but detents increase the required separating force, first to overpower the detent and then to overcome the frictional retention of mating contacts of the connectors. Contact friction combined with a detent may not provide sufficient retention; the connectors remain vulnerable to accidental or unintended separation.
A retainer having a latch and a catch is known for blocking connectors of a plugged-in connector pair against accidental separation. This form of retainer is considered to be positive; its design should be such as to require deliberate release before the connectors can be separated. Where a latch-and-catch locking device is used, the latch must be pried or otherwise manipulated as a preliminary to unplugging the connectors. The latch must be held in its released condition until separation of the connectors has progressed far enough to forestall reengagement of the latch and catch.